Electrical connector assembly having improved guiding means

ABSTRACT

A male connector ( 10 ) includes first and second individual housing portions ( 28, 30 ) engaging with each other, a number of substrates ( 16 ) held by the first housing portion and a number of signal contacts ( 18 ) and a number of grounding terminals ( 20 ) held by the second housing portion with the signal contacts confronting the grounding terminals. Each substrate has a first edge ( 108 ) and a second edge ( 110 ) orthogonal with the first edge. The first edges of the substrates are hidden behind corresponding lead-in bars ( 44 ) of the first housing portion and the second edges of the substrates are sandwiched between and removeably held by the signal contacts and the grounding terminals. The second edges are pushed toward the signal contacts by the grounding terminals because the grounding terminals are stronger than the signal contacts. A female connector ( 12 ) mateable with the male connector includes a dielectric member ( 22 ) and a number of signal contacts ( 24 ) and a number of grounding terminals ( 26 ) retained in the dielectric member in face-to-face relationship. The signal contacts straddle on a bottom surface ( 128 ) of the dielectric member. The male and the female connectors have a guiding means for guiding the connectors to correctly mate with each other.

CROSS-REFERENCES TO RELATED APPLICATIONS

This patent application is a continued-in-part (CIP) application ofpatent application Ser. No. 09/746,088, filed on Dec. 21, 2000 now U.S.Pat. No. 6,390,857, and a Co-pending Application of Patent Applicationwith an unknown serial number, entitled “ELECTRICAL CONNECTOR HAVINGIMPROVED GROUNDING TERMINALS”, invented by the same inventors as thispatent application, another co-pending application of application withan unknown serial number, entitled “ELECTRICAL CONNECTOR HAVING PRINTEDSUBSTRATES THEREIN ELECTRICALLY CONTACTING CONDUCTIVE CONTACTS THEREOFBY SOLDERLESS”, invented by the same inventors as this patentapplication; and another co-pending application with an unknown serialnumber, entitled “ELECTRICAL CONNECTOR HAVING IMPROVED CONTACTS”,invented by Timothy Brain Billman, all assigned to the same assignee andfiled on the same date with this application. U.S. Pat. No. 6,375,508 isalso related hereto.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to an electrical connector assembly, andparticularly to an electrical connector assembly having improved guidingmeans for accurately guiding a male connector thereof to mate with afemale connector thereof.

2. Description of the Related Art

Fleck Research, the worldwide leader in information technology andmarket intelligence, announced an article, entitled “A View from theBackplane”, on Jan. 07, 2002 at the website,http://www.fleckresearch.com/news/en₁₃99-10-18.htm. This articleintroduced some backplane connectors, for example, Teradyne and Molex'sHDM (High Density Metric) family of 2.0 mm connectors, FCI's (Berg)Metral HB connectors, FCI's new HMHS (Hard Metric High Speed) connectorand AMP's Z-PACK HS3 connector. These connectors have common features ofhigh-density, high-speed and strict demand for impedance and crosstalkcontrol.

U.S. Pat. Nos. 6,171,115 and 6,267,604, both issued to Tyco ElectronicsCorporation, each disclose a backplane connector including a dielectrichousing and a plurality of circuit boards held in the housing. Thehousing includes a front housing and an organizer engaging with thefront housing. Each circuit board provides a plurality of conductivetracks extending from a mating interface thereof to a mounting edgethereof. The mating interface extends beyond the front housing to matewith a mating connector. The mounting edge is secured with conductiveterminals by soldering before the mounting edge and the terminals areinserted in slots of the organizer. U.S. Pat. No. 6,083,047, issued toBerg Technology, Inc., discloses an alternate backplane connectorincluding a connector body of dielectric material and a plurality ofintegrated PCB modules arranged parallel, side-by-side inserted to theconnector body. Each PCB module includes a pair of substrates, aplurality of terminals soldered onto an inner surface of each substrateand an insulating spacer sandwiched between the inner surfaces of thesubstrates. U.S. Pat. No. 6,168,469, issued to Hon Hai Precision Ind.Co., Ltd. discloses a similar backplane connector that the contacts aresoldered to printed circuit boards. These connectors have severaldisadvantages. First, it requires a step of soldering the contacts tothe substrates by Surface Mounting Technology (SMT). The SMT requiresexpensive machine, thereby increasing the manufacturing cost of theconnectors. Second, when the substrates, which are originally designedfor signal transmission are required to be replaced by substrates forpower transmission, the substrates together with the contacts must bediscarded. This is not economy. Third, there is no means for guidingcontacts of a mating connector to engage with the mating surface of thesubstrates. Therefore, there is a disadvantage that noble metal platedon contacting portions of the signal contacts may wear off due to theirwiping action against the corners of the edge of the substrate.

U.S. Pat. Nos. 6,293,827 and 6,174,202, both issued to Teradyne Inc.,U.S. Pat. No. 6,343,955, issued to Berg Technology Inc., and U.S. Pat.No. 6,299,484, issued to Framatome Connectors International (FCI), eachdisclose a backplane connector having a plurality of contacts stampedand formed from metal ribs. Each contact has a mating end for engagingwith a contact of a mating connector and a mounting end for mounting toa mother board. These contacts are relatively long and manufacturedcostly.

U.S. Pat. No. 5,980,321, issued to Teradyne Inc., and U.S. Pat. No.6,220,896, issued to Berg technology Inc., each disclose a backplaneconnector including a plate between every two rows of signal contacts.One of the disadvantages of these backplane connectors is that thegrounding plate has no spring arm for reliably contacting acorresponding grounding element of a mating connector. So, disconnectionmay happen between the grounding plate of this backplane connector andthe grounding element of the mating connector. Hence, an improvedelectrical connector is required to overcome the disadvantages of theprior art.

SUMMARY OF THE INVENTION

A first objective of the present invention is to provide an electricalconnector having substrates therein moveably engage with correspondingconductive contacts thereof such that it is very convenient to replacesome of the substrates with other devices.

A second objective of the present invention is to provide an electricalconnector having means located in front of substrates thereof forguiding contacts of a mating connector to contact correspondingconductive elements on the substrates.

A third objective of the present invention is to provide an electricalconnector assembly having an improved guiding means for guiding a maleconnector thereof to correctly mate with a female connector thereof.

A fourth objective of the present invention is to provide an electricalconnector having a plurality of contacts that are secured to aninsulative member thereof in a unique way.

To obtain the above objectives, an electrical connector assemblycomprises a male connector mountable to a first printed circuit board, afemale connector mountable to a second printed circuit board and aguiding means for guiding the male connector to mate with the femaleconnector correctly. The male connector include first and secondindividual housing portions engageable with each other, a plurality ofsubstrates held between the firs and the second housing portions and aplurality of signal contacts and a plurality of grounding terminalsattached to the second housing portion in face-to-face relationship.Each substrate has a plurality of first conductive pads adjacent a firstedge thereof and a plurality of second conductive pads adjacent a secondedge thereof which is orthogonal with the first edge. The first housingportion provides a plurality of wedge-shaped lead-in bars in front ofthe substrates for guiding contacts of the female connector to contactcorresponding first conductive pads of the substrates. The second edgesof the substrates extend out of the first housing portion into thesecond housing portion to be removeably sandwiched between correspondsignal contacts and corresponding grounding terminals.

The female connector includes a dielectric member having a plurality ofelongate wafers and defining a channel between every two adjacentwafers, a plurality of signal contacts and a plurality of groundingterminals received in the channels with each grounding terminalconfronting several signal contacts. Each grounding terminal has fourretention latches and eight contacting arms at one side thereof and fivetail portions at an opposite side thereof. The contacting arms aresorted in four pairs and between each pair there is a retention latch.Each retention latch has a cap portion at a top end thereof attached tothe dielectric member, thereby retaining the grounding terminals to thedielectric member. The contacting arms are configured to engage withgrounding elements of the female connector while the tail portions areconfigured to electrically contact corresponding conductive pads on thesecond printed circuit board. In a preferred embodiment, the contactingarms of the grounding terminals are somewhat stronger than thecontacting portions of the signal contacts, so, the substratessandwiched by the contacting arms and the contacting portions are pushedby the contacting arms toward the contacting portions to secure theelectrical connection between the contacting portions and the secondconductive pads. Retention portions of the signal contacts each define aslot such that the retention portions may straddle upon correspondingprotrusions on a bottom surface of the dielectric member.

The guiding means includes a pair of frames, which define a chamberbetween each frame and an outmost lead-in bar of the first housingportion, at opposite ends of the first housing portion and a pair ofguiding posts at opposite ends of the dielectric member. The guidingposts are received in corresponding chambers before the first housingportion engages with the dielectric member for guiding the maleconnector to mate with the female connector. Each frame provides twoguiding keys unsymmetrically located in an inner surface thereof andeach guiding post defines two guiding cuts in accordance with theguiding keys. The male connector can only mate with the female connectorwhen the guiding keys are accommodated by corresponding guiding cuts,thereby providing anti-blindmating function.

Other objects, advantages and novel features of the invention willbecome more apparent from the following detailed description of thepresent embodiment when taken in conjunction with the accompanyingdrawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an assembled perspective view of a male connector and a femaleconnector respectively mounted onto a first and a second printed circuitboards (PCBs);

FIG. 2 is a front-top perspective view of the male connector mounted onthe first PCB;

FIG. 3 is an exploded perspective view of first and second housingportions of the male connector;

FIGS. 4A and 4B are enlarged sections of FIG. 3;

FIG. 5 is a rear-top perspective view of the first housing portion inFIG. 3;

FIGS. 6A-6C are enlarged perspective views of signal contacts of themale connector in three embodiments;

FIG. 7 is an enlarged perspective view of a grounding terminal of themale connector;

FIGS. 8A-8B are opposite perspective views of a substrate of the maleconnector;

FIG. 9 is a cross-sectional view of a section of the second housingportion and the substrates attached to the second housing portion;

FIG. 10 is a top-front perspective view of the female connector mountedon the second PCB;

FIGS. 11A-11B are enlarged top and bottom perspective views of a sectionof the female connector in FIG. 10;

FIG. 12 is an enlarged cross-sectional view of a section of the assemblyof the male and the female connectors;

FIGS. 13A-13B are perspective views of the assembly of the male andfemale connectors taken from different perspectives, wherein thehousings are removed to clearly show the engagement of the substrateswith the signal contacts and the grounding terminals; and

FIG. 14 is a top planar view of a PCB of an alternative embodiment ofthis invention.

DESCRIPTION OF THE PREFERRED EMBODIMENT

Referring to FIGS. 1-3, 6A-8B and 10, an electrical connector assembly 1of the present invention includes a male connector 10 mounted on a firstprinted circuit board (PCB) 3 and a female connector 12 mounted on asecond PCB 5. The male connector 10 includes an insulative housing 14, aplurality of substrates 16 and a plurality of signal contacts 18 andgrounding terminals 20 received in the housing 14. The female connector12 includes an insulative housing 22, a plurality of signal contacts 24and grounding terminals 26 received in the housing 22.

Referring to FIGS. 3-9, the housing 14 includes first and secondindividual housing portions 28, 30 engageable with each other. The firsthousing portion 28 has a front surface 32 for mating with the femaleconnector 12, a rear surface 34 and a lower surface 36 in orthogonalwith the rear surface 34. The first housing portion 28 defines aplurality of passageways 38 through the rear surface 34, the lowersurface 36 and terminating at the front surface 32. The first housingportion 28 provides a row of blocks 40 on a top section of the rearsurface 34 and two guiding ribs 42 near opposite ends of the row ofblocks 40. The guiding ribs 42 downwardly extend throughout the heightof the rear surface 34 for guiding the first housing portion 28 toaccurately engage with the second housing portion 30. The first housingportion 28 further provides a plurality of lead-in bars 44 near thefront surface 32. Each lead-in bar 44 is wedge-shaped in cross-sectionfor facilitating mating with the female connector 12. Each lead-in bar44 provides three branches 46 rearwardly extending into a correspondingpassageway 38 for securing the substrates 16 in the passageways 38 ofthe first housing portion 28, respectively. The first housing portion 28again defines a row of notches 48 (FIG. 5) in a middle surface 50thereof between and parallel with the front and the rear surfaces 32, 34for purpose disclosed in detail below.

The second housing portion 30 has a generally sofa-like shape, andincludes a rectangular base portion 52 defining a plurality of channels54 in an upper surface 56 thereof, a backrest portion 58 upwardlyextending from a rear edge of the upper surface 56 of the base portion52 and two elongate stand-offs 60 depending on front and rear edges of abottom surface 62 of the base portion 52. Between every two nearchannels 54 there is an elongate wafer 64 which defines four recesses 66in the upper surface 56 and provides an embossment 68 in each recess 66.The base portion 52 provides a row of blocks 70 on a front face 72thereof for being engageably received in corresponding notches 48 of thefirst housing portion 28. The backrest portion 58 defines a row ofnotches 74 in a top end 76 thereof for engageably receivingcorresponding blocks 40 and two guiding tracks 78 at opposite sideportions 80 thereof for receiving the guiding ribs 42 of the firsthousing portion 28.

The signal contact 18 includes a contacting portion 82 for mating withthe substrate 16 and a tail portion 84 for mating with the first PCB 3.The contacting portion 82 offsets a predetermined distance from the tailportion 84 in a traverse direction of the signal contact 18 (FIG. 9).The tail portion 84 is a press-fit tail for engageably inserting into acorresponding plated hole 86 of the first PCB 3. A signal contact 18′according to a second embodiment has an inclined tail portion 84′ forpressing against a corresponding conductive pad 88 of a first PCB 3′according to a second embodiment (FIG. 14) of the present invention. Asignal contact 18″ according to a third embodiment of the presentinvention includes a contacting portion 82″ having two spring arms 90, apress-fit tail portion 84″ and an inclined retention portion 92 betweenthe contacting portion 82″ and the tail portion 84″. The retentionportion 92 defines a slot 94 so that it may straddle upon a bottomsurface of the second housing portion 30.

The grounding terminal 20 includes an elongate base portion 96, fivepress-fit tail portions 98 downwardly extending from a lower side of thebase portion 96 and four retention latches 100 and eight contacting arms102 upwardly extending from an upper side of the base portion 96. Besideopposite sides of each retention latch 100, there are two contactingarms 102. Each retention latch 100 is generally 7-shaped and has a capportion 104 at a top end thereof. The cap portion 104 defines an opening106 for receiving a corresponding embossment 68 of the second housingportion 30. The substrate 16 provides a first row of first gold fingers112 on opposite surfaces near a first edge 108 thereof, a second row ofsecond gold fingers 114 on the opposite surfaces near a second edge 110thereof and a plurality of traces 116 connecting the first gold fingers112 to corresponding second gold fingers 114. The first row isperpendicular to the second row. The substrate 116 defines three grooves118 in the first edge 108 for engageably receiving correspondingbranches 46 of a corresponding lead-in bar 44.

Upon the assembling of the male connector 10, the substrates 16 areinserted into corresponding passageways 38 of the first housing portion28 from the rear surface 34 toward the front surface 32. The first edge108 of each substrate 16 is hidden behind a corresponding lead-in bar 44with the grooves 118 thereof engageably receiving corresponding branches46. The second edge 110 of each substrate 16 partially extendsdownwardly beyond the lower surface 36 with the second gold fingers 114exposing out of the first housing portion 28. The signal contacts 18 andthe grounding terminals 20 are inserted into corresponding channels 54of the second housing portion 30 with eight signal contacts 18 lying inone side of the channel 54 and one grounding terminal 20 lying in anopposite side of the channel 54 such that the signal contacts 18confront the grounding terminal 20. The cap portion 104 of the groundingterminal 20 is received in a corresponding recess 66 with the opening106 thereof fixedly receiving a corresponding embossment 68, therebyattaching the grounding terminals 20 to the first housing portion 28.The first housing portion 28 together with the substrates 16 are thenassembled to the second housing portion 30 such that the second edges110 of the substrates 16 are received in corresponding channels 54 ofthe second housing portion 30. The contacting portions 82 of the signalcontacts 18 and the contacting arms 102 of the grounding terminals 20wipe along and electrically contact corresponding second gold fingers114 of the substrates 16. The second edge 110 of the substrate 16 issandwiched between the contacting portions 82 of the signal contacts 18and the contacting arms 102 of the grounding terminal 20. The contactingarms 102 are somewhat stronger than the contacting portions 82 such thatthe second edge 110 is pushed by the contacting arms 102 toward thecontacting portions 82 to ensure electrical connections between thesecond gold fingers 114 and the contacting portions 82 of the signalcontacts 18 (FIG. 9 and FIGS. 13A-13B).

Referring to FIGS. 10, 11A and 11B, the housing 22 of the femaleconnector 12 provides a plurality of elongate wafers 120 and defines aplurality of channels 122 each between two near wafers 120. Each channel122 receives eight signal contacts 24 and a grounding terminal 26 atopposite sides thereof. The signal contact 24 and the grounding terminal26 of the female connector 12 are respectively similar to the signalcontact 18″ and the grounding terminal 20 of the male connector 10 instructure but different in dimensions. The housing 22 provides a pair ofelongate stand-offs 124 and a pair of guiding poles 126 (only one isshown in FIG. 11B) on a bottom surface 128 thereof. The housing 22further provides a plurality of protrusions 130 on the bottom surface128. The signal contact 24 includes an inclined retention portion 132having a pair of ribs 134 and defining a slot 136 between the ribs 134.The retention portion 132 straddles on the protrusion 130 with the ribsengageably sandwiching the protrusion 130, thereby assisting retainingthe signal contact 24 to the housing 22.

Referring to FIGS. 12 and 13A, 13B, when the male connector 10 mateswith the female connector 12, the wedged lead-in bars 44 of the maleconnector 10 push the contacting portions of corresponding signalcontacts 24 and the contacting arms of corresponding grounding terminals26 to move away from each other so that they may smoothly slide toelectrically contact corresponding first gold fingers 112 without wipingagainst corners of the first edges 108 of the substrates 16. Therefore,a disadvantage that noble metal plated on the contacting portions 82 ofthe signal contacts may wear off due to their wiping action against thecorners of the edge of the substrate 16 can be prevented in the presentinvention. The tail portions 84, 98 of the signal contacts 18 and thegrounding terminals 20 of the male connector 10 arranged in a same roware inserted into a same row of plated holes 86 of the first PCB 3. Sodoes the female connector 12.

Referring to FIG. 14, in accordance with the signal contacts 18′ of thesecond embodiment, the first PCB 3′ of the second embodiment providesfive rows of plated through-holes 86′ and four pairs of rows ofconductive pads 88, each pair being located between every two near rowsof plated through-holes 86′. When the male connector 10 is mounted ontothe first PCB 3′, the tail portions 98 are received in correspondingthrough-holes 86′ by press-fit while the tail portions 84′ of the signalcontacts 18′ electrically contact corresponding conductive pads 88 by adepressing force acting on the tail portions 84′.

As is shown in FIGS. 1, 2 and 10, the connector assembly 1 includes apair of guiding means 138 at opposite sides thereof for guiding the maleconnector 10 to correctly mate with the female connector 12. Eachguiding means 138 includes a frame 140 at each side of the first housingportion 28 and a chamber 142 between the frame 140 and an near lead-inbar 44. The frame 140 provides two guiding keys 144 located on an innersurface 146 thereof and extending in a front-to-rear direction. Eachguiding means 138 also includes a guiding post 148 at each side of thehousing 22 with a wedged top portion 150 extending beyond a top face ofthe housing 22. The guiding post 148 defines two guiding cuts 152unsymmetrically in an outer surface 154 thereof, located correspondingto the guiding keys 144. When the male connector 10 mates with thefemale connector 12, the wedged top portions 150 are first inserted intocorresponding chambers 142 and the guiding keys 144 are received incorresponding guiding cuts 152 before the lead-in bars 44 touch thehousing 22, the signal contacts 24 and the grounding terminals 26. Whenthe guiding posts 148 are wholly received in the corresponding chambers142, the male connector 10 securely mates with the female connector 12.

Comparing with the prior arts, this invention has a lot of advantages.First, since the substrates 16 are removeably held in the first housingportion 28, it is very convenient to replace any one of the substrates16 with another substrate for a different function. Second, since thefirst edges 108 of the substrates 16 are covered by the lead-in bars 44,plated noble metal on the contacting portions 82 of the signal contacts18 can obtain a better protection against wearing. Third, the elongategrounding terminals 20 each are attached to the second housing portion30 by four retention latches 100, the grounding terminals 20 can besecurely attached to the second housing portion 30. Fourth, since thesubstrates 16 are pushed by the grounding terminals 20 toward the signalcontacts 18, secure electrical connections are established between theconductive pads 114 and the contacting portions 82 of the signalcontacts 18.

It is to be understood, however, that even though numerouscharacteristics and advantages of the present invention have been setforth in the foregoing description, together with details of thestructure and function of the invention, the disclosure is illustrativeonly, and changes may be made in detail, especially in matters of shape,size, and arrangement of parts within the principles of the invention tothe full extent indicated by the broad general meaning of the terms inwhich the appended claims are expressed.

What is claimed is:
 1. An electrical connector assembly comprising: amale connector including first and second individual housing portionsengaging with each other, a plurality of signal contacts and a pluralityof grounding terminals attached to the second housing portion and aplurality of substrates held by the first housing portion, eachsubstrate having an edge moveably sandwiched by the signal contacts andthe grounding terminals, the first housing portion providing two framesat opposite sides thereof, each frame defining a chamber and providingat least one guiding key on an inner surface thereof; and a femaleconnector including a dielectric member for engaging with the firsthousing portion, a plurality of signal contacts and a plurality ofgrounding terminals attached to the dielectric member for electricallyengaging with the substrates, the dielectric member having a pair ofguiding posts at opposite ends thereof, each guiding post defining atleast one guiding cut in an outer surface thereof, the guiding postsbeing inserted in corresponding chambers of the first housing portionbefore the first housing portion engages with the dielectric member, theguiding posts being insertable into the corresponding chambers only whenthe guiding keys are received in corresponding guiding cuts.
 2. Theelectrical connector as claimed in claim 1, wherein the first and thesecond housing portions each provide a row of blocks and a row ofnotches, the blocks of one of the first and the second housing portionsbeing fixedly received in corresponding notches of the other of thefirst and the second housing portions, thereby joining the first and thesecond housing portions together.
 3. The electrical connector as claimedin claim 2, wherein one of the first and the second housing portionsprovides at least one guiding rib and the other of the first and thesecond housing portions provides at least one guiding track, the atleast one guiding rib engaging with the at least one guiding trackbefore the engagement of the blocks with the notches of the first andthe second housing portions.
 4. The electrical connector assembly asclaimed in claim 1, wherein the second housing portion has a pluralityof elongate wafers and defines a plurality of channels between thewafers, each channel receiving one of the grounding terminals and atleast one of the signal contacts confronting said one of the groundingterminal.
 5. The electrical connector assembly as claimed in claim 4,wherein the first housing portion has a front surface for mating withthe female connector and each substrate has a first edge adjacent thefront surface and a second edge inserted in a corresponding channel ofthe second housing portion.
 6. The electrical connector assembly asclaimed in claim 5, wherein each substrate has a plurality of firstconductive pads adjacent the first edge thereof, a plurality of secondconductive pads adjacent the second edge thereof and a plurality ofconductive traces connecting the first conductive pads withcorresponding second conductive pads.
 7. The electrical connector asclaimed in claim 6, wherein the first housing portion defines aplurality of passageways in alignment with the channels, the substratesbeing received in the passageways of the first housing portion,respectively.
 8. The electrical connector as claimed in claim 6, whereinthe first housing portion provides a plurality of lead-in bars locatedadjacent the front surface thereof and covering the first edges of thesubstrates so that the signal contacts and grounding terminals of thefemale connector are prevented from wiping against of corners of thefirst edges of the substrates when the first housing portion engageswith the dielectric member.
 9. The electrical connector as claimed inclaim 8, wherein the lead-in bars are wedge-shaped in cross-sections.10. The electrical connector as claimed in claim 9, wherein the lead-inbars each have at least one branch rearwardly extending into passagewaysdefined in the first housing portion, and wherein the substrates eachdefine at least one groove at the first edge thereof, the at least onebranch being received in the at least one groove.
 11. An electricalconnector comprising: a housing portion having a front surface adaptedfor mating with a mating connector and defining a plurality ofpassageways through the front surface, the housing portion providing aplurality of lead-in bars adjacent the front surface; a plurality ofsubstrates each having a row of first conductive pads adjacent a firstedge thereof, a row of second conductive pads adjacent a second edgethereof and a plurality of conductive traces connecting the firstconductive pads with corresponding second conductive pads, thesubstrates being received in corresponding passageways of the housingportion with the first edges thereof being hidden behind correspondinglead-in bars wherein the lead-in bars are wedge shaped in cross-sectionsand wherein the lead-in bars each have at least one branch rearwardlyextending into the passageway of the housing portion and wherein thesubstrates each define at least one groove at the first edge thereof,the at least one branch being received in the at least one groove. 12.An electrical connector assembly comprising: a first connector mountedon a first printed circuit board and including a first insulativehousing defining a first mating port with a plurality of blade-likemating sections therein in a spatial relationship with one another; apair of frames positioned at two opposite lengthwise ends of the firsthousing; a second connector mounted on a second printed circuit boardand including a second insulative housing defining a second mating port,a plurality of elongated wafers side by side arranged with one anotherso as to form a channel between every adjacent two wafers, two oppositeends of each of the wafers being spaced from longitudinal walls of thesecond housing; a plurality of terminals disposed along each of saidwafers; and a pair of guiding posts disposed at two opposite lengthwiseends of the second housing, wherein when mated, the blade-like matingsections are received in the corresponding channels, respectively, andlongitudinal walls of the first housing, along a lengthwise directionthereof, are received between the longitudinal walls of the secondhousing and the wafers so that the first housing is generally enclosedby said second housing in a transverse direction perpendicular to saidlengthwise direction, while the guiding posts are received in thecorresponding frames respectively so that the second housing isgenerally enclosed by said first housing in the lengthwise direction.